Carbon fiber centrifuge rotors are known. Accordingly to my earlier U.S. Pat. No. 5,643,168 entitled Compression Molded Composite Material Fixed Angle Rotor issued Jul. 1, 1997 to Piramoon et al, mixed carbon fiber (about 60%) and resin (about 40%) are compression molded to form a net shaped central rotor body with integrally formed sample tube apertures. Typically, this body is frustum shaped between an apex end and a base end. The sample tube apertures are symmetrically arranged about the spin axis of the rotor body and open to the apex end of the rotor. The sample tube apertures extend angularly outward to their closed bottom ends, these ends being near the base end of the rotor and more distant from the spin axis of the rotor than the openings of the sample tube apertures at the apex end. The generally frustum shaped rotor body is provided with circular peripheral steps, these steps being configured to receiving windings. The rotor is wound with continuous carbon fiber at the steps and finished by machining and painting.
It is highly desirable to reduce the weight of a centrifuge rotor to the maximum extent. This is a primary reason why carbon fiber rotors are utilized; they are 40% lighter than their metal equivalents.
Scalloped rotors are known. Until this disclosure, these rotors have all been constructed from carefully machined metal billets. In the case of metal centrifuge rotors, producing differing exterior contours only requires machining. Scalloped bottom metal rotors are known to have problems. Specifically, their lightened metal construction must be constantly inspected for failure. Further, such rotors are now manufactured with carefully machined and dimensioned thin sections which "fuse", the rotor. When breakage is observed at the fused section, the rotor is taken out of service.
Machining of carbon fiber interferes with its structural integrity. For this reason, scalloped rotor constructions have not been utilized with carbon fiber. Instead, carbon fiber rotors have thus far been compression molded without scallops.